Re: Relational vs. PICK/Object DBMS

Sir:

I suspect the following would work, theoretically. :-)

> Sorry for the notation. I will try to restate the problems in English.
>
> 1) Suppose you have a bunch of attributes that describes the entities in
> your database.
> Suppose any attribute is optional for any entity.
>
> a) For a given set of attributes
> - find all the entities that for any attribute in the given set have at
> least one value.

Create a definition of a given set of attributes then:

LIST MyFile WITH GivenAttributes

> - also find the values of the given attributes

Create an output definition then:

LIST MyFile WITH GivenAttributes _at_ID GivenAttributeValues

where AttributesWithValue is defined as an output format as defined

> b) For a given entity
> - find all the attributes that have at least one value for the given
entity

Create a definition for a non-empty entity then:

LIST MyFile 'EntityID' WITH AttributesWithValueList

> - also find the values of the attributes for the given entity

Create an output definition for a non-empty entity then:

LIST MyFile 'EntityID' NonEmptyAttributeValues

If you provied a concrete example then the queries will be more concrete. Hope this helps though.

Bill Received on Sun Apr 25 2004 - 04:37:17 CEST